Surgical Palliation for Hypoplastic Left Heart Syndrome

Abstract

I n 2010, Ohye and colleagues 1 published the results of a prospective, random-ized trial comparing the effect of the type of shunt used to establish controlled pulmonary blood flow. This report compared the modified Blalock-Taussig shunt (BTS) with a small right ventricle to pulmonary artery conduit or shunt (RVPA) on outcomes in neonates requiring the life-saving Norwood palliation for hypoplastic left heart syndrome (HLHS). Known as the SVR trial (Single Ventricle Reconstruction), this is the only prospective, randomized study undertaken to date to directly compare different surgical strategies in the treatment of complex congenital heart disease. The hopes were high for this trial: while surgeons continued to debate the superiority of using a BTS or an RVPA shunt (largely based on single-institution retrospective reports), the promise of a prospective comparison study in definitively determining the best operation to perform was exciting and offered hope for clarification of surgical strategy. As this important cohort of children grows up, new insights are being sequentially revealed (or at least reinforced) about the complex realities of the lives of children (and thereby their families) with HLHS. Unfortunately, as Newburger and colleagues 2 have nicely documented in this lat-est follow-up analysis published in this issue of Circulation, the question of which operation (or specifically which source of pulmonary blood flow), either the BTS or RVPA shunt, confers optimum outcomes remains elusive or, to be more cynical, possibly unimportant. The reality of current practice is that centers and individual surgeons taking care of children with HLHS remain split in terms of shunt source. Surgeons tend to do what they do best. Maybe that is just fine. Newburger and colleagues 3 previously shared information about trial par-ticipants' outcomes at 3 years of follow-up. Their current report brings us provocative , updated outcomes data. With a minimum individual patient follow-up duration of 6 years, this report updates outcomes in the SVR cohort in terms of transplant-free survival, right ventricular function, and patient morbidity. The results are sobering and worthy of careful consideration. Of the original 549 en-rollees, only 331 children (≈60%) are alive without having had to undergo a heart transplant operation. Thus, when a parent asks us (or, more commonly now, when a prospective parent asks us during a fetal consultation), what is the probability that my child will live to school age, we should tell them that in the only prospective trial ever conducted for children with HLHS, the overall probability is ≈60%. We should also tell them that only 4% of patients in this large trial either needed (good news maybe) or were able to receive (concerning) a heart transplant. We should tell them that roughly half of surgeons perform an extracardiac Fontan operation, whereas the rest of our colleagues perform a lateral atrial tunnel as the final planned stage of palliation, and we really do not know which approach